package io2;

import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

public class Test {
    public static void main(String[] args) throws IOException {
        FileOutputStream fos = new FileOutputStream("fos.txt");

        String s = "a";
        int a = 65;
        char c;
        byte[] data = new byte[1];
        while (a <65+26) {
           c=(char)a;
           fos.write(String.valueOf(c).getBytes(StandardCharsets.UTF_8));
           a++;
        }
        fos.close();
    }
}
